The present application relates to heavy vehicle braking systems, and is particularly directed to a foot brake valve apparatus for a heavy vehicle braking system, such as a truck braking system.
One type of foot brake valve apparatus includes a foot brake valve having a valve body and parallel supply pressure ports on one side of the valve body and delivery pressure ports on an opposite side of the valve body. A primary supply pressure port and a primary delivery pressure port are provided for a primary braking circuit. A secondary supply pressure port and a secondary delivery pressure port are provided for a secondary braking circuit. The primary and secondary supply pressure ports are on the one side of the valve body, and the primary and secondary delivery pressure ports are on the opposite side of the valve body. A drawback in this known type of foot brake valve apparatus is that a single pressure sensing package is unable to be installed on the valve body to access the four different pressure ports to measure pressure at each of the four pressure ports. It would be desirable to provide a foot brake valve apparatus in which a single pressure sensing package can be installed on the valve body to access all four pressure ports so that pressure measurements can be obtained at each of the pressure ports.